Anatomy of a Web Service: XML, SOAP and WSDL for Platform-independent Data Exchange

Anatomy of a Web Service: XML, SOAP and WSDL for Platform-independent Data Exchange: "Most applications are developed to interact with users; the user enters or searches for data through an interface and the application then responds to the user's input. A Web service does more or less the same thing except that a Web service application communicates only from machine to machine or application to application. There is often no direct user interaction. A Web service basically is a collection of open protocols that is used to exchange data between applications. The use of open protocols enables Web services to be platform independent. Software that are written in different programming languages and that run on different platforms can use Web services to exchange data over computer networks such as the Internet. In other words, Windows applications can talk to PHP, Java and Perl applications and many others, which in normal circumstances would not be possible."